California's Drought: why, when and how long?

After three consecutive years of below-normal rainfall, California faces its most severe drought emergency in decades. Dr. William (Bill) Patzert, a JPL scientist and often called the "Prophet of California climate", will discuss just what's behind our current drought -- the why, when and how long.

The current reality: Governor Jerry Brown has called for Californians to voluntarily reduce water use by 20 percent. Mandatory rationing could be ordered soon so that homes, businesses and farms don't run dry over the summer. Wildfire danger is unusually high. How did we get into this drought? In part, blame it on the Pacific Decadal Oscillation, or "PDO", a slowly oscillating pattern of sea surface temperatures in the Pacific Ocean. At the moment, the PDO is in its negative phase—a condition historically linked to extreme high-pressure ridges that block West Coast storms and give the Midwest and East Coast punishing winters. "California's history is written in great droughts," Patzert says. To find out how long this drought will last, attend his talk!